From: Fair Chiz (s3s9@xxxxxxxxx)
Date: Wed Apr 11 2001 - 04:07:43 GMT-3
Heres the scenario, 4 routers connected in series, the
middle two routers using IBGP and eigrp, the
outer two strictly EBGP.
R1--R2--R3--R4
R1= AS100
R2= AS200
R3= AS200
R4= AS300
R1 has four loopbacks,
11.11.1.0,11.11.2.0,11.11.3.0,11.11.4.0
R4 has four loopbacks,
55.55.1.0,55.55.2.0,55.55.3.0,55.55.4.0,
Heres the problem:
R2 has a route to the next-hop for R4's routes
R1 has a route to the next-hop for R1's routes
R2 doesnt list the loopbacks from R4 in its route
table (but they are in its BGP table)
R3 doesnt list the loopbacks from R1 in its route
table (but they are in its BGP table)
debug shows:
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
=-=-=-=-=-=-
BGP: 10.2.2.6 rcv UPDATE about 55.55.1.0/24, next hop
10.1.1.10, path 300 metric 0
BGP: 10.2.2.6 rcv UPDATE about 55.55.2.0/24, next hop
10.1.1.10, path 300 metric 0
BGP: 10.2.2.6 rcv UPDATE about 55.55.3.0/24, next hop
10.1.1.10, path 300 metric 0
BGP: 10.2.2.6 rcv UPDATE about 55.55.4.0/24, next hop
10.1.1.10, path 300 metric 0
BGP: 10.2.2.6 rcv UPDATE about 10.1.1.4/30, next hop
10.2.2.6, path metric 0
BGP: nettable_walker 10.1.1.4/255.255.255.252 calling
revise_route
BGP: revise route installing 10.1.1.4/255.255.255.252
-> 10.2.2.6
BGP: nettable_walker 55.55.1.0/255.255.255.0 not
synchronized
BGP: nettable_walker 55.55.2.0/255.255.255.0 not
synchronized
BGP: nettable_walker 55.55.3.0/255.255.255.0 not
synchronized
BGP: nettable_walker 55.55.4.0/255.255.255.0 not
synchronized
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
=-=-=-=-=-=
OK, so I set no sync, and everything works, but
somehow I'm not quite satisfied,
I understand IBGP learned routes won't be advertised
to EBGP neighbors unless sync'd
but should IBGP neighbors share (and use) routes
learned via EBGP without having to redistribute
via an igp? Running eigrp on R1 and R4 is not an
option.
Thanks,
Rob
configs below:
R1
*************************************
interface Loopback101
ip address 11.11.1.1 255.255.255.0
!
interface Loopback102
ip address 11.11.2.1 255.255.255.0
!
interface Loopback103
ip address 11.11.3.1 255.255.255.0
!
interface Loopback104
no ip address
!
interface Loopback105
ip address 11.11.4.1 255.255.255.0
interface Serial0
ip address 10.1.1.1 255.255.255.252
no ip mroute-cache
no fair-queue
!
router bgp 100
network 11.11.1.0 mask 255.255.255.0
network 11.11.2.0 mask 255.255.255.0
network 11.11.3.0 mask 255.255.255.0
network 11.11.4.0 mask 255.255.255.0
neighbor 10.1.1.2 remote-as 200
!
R2
*************************************
!
interface Loopback100
ip address 10.2.2.5 255.255.255.255
!
interface Serial0
ip address 10.1.1.2 255.255.255.252
no fair-queue
clockrate 1000000
!
interface Serial1
ip address 10.1.1.5 255.255.255.252
clockrate 1000000
!
router eigrp 100
network 10.0.0.0
!
router bgp 200
network 10.1.1.4 mask 255.255.255.252
neighbor 10.1.1.1 remote-as 100
neighbor 10.2.2.6 remote-as 200
neighbor 10.2.2.6 update-source Loopback100
!
R3
**************************************
interface Loopback100
ip address 10.2.2.6 255.255.255.255
!
interface Serial0
ip address 10.1.1.6 255.255.255.252
no fair-queue
!
interface Serial1
ip address 10.1.1.9 255.255.255.252
router eigrp 100
network 10.0.0.0
!
router bgp 200
network 10.1.1.4 mask 255.255.255.252
neighbor 10.1.1.10 remote-as 300
neighbor 10.2.2.5 remote-as 200
neighbor 10.2.2.5 update-source Loopback100
!
R4
******************************************
interface Loopback101
ip address 55.55.1.1 255.255.255.0
!
interface Loopback102
ip address 55.55.2.1 255.255.255.0
!
interface Loopback103
ip address 55.55.3.1 255.255.255.0
!
interface Loopback104
no ip address
!
interface Loopback105
ip address 55.55.4.1 255.255.255.0
!
interface Serial1
ip address 10.1.1.10 255.255.255.252
clockrate 1000000
!
router bgp 300
network 55.55.0.0 mask 255.255.0.0
network 55.55.1.0 mask 255.255.255.0
network 55.55.2.0 mask 255.255.255.0
network 55.55.3.0 mask 255.255.255.0
network 55.55.4.0 mask 255.255.255.0
neighbor 10.1.1.9 remote-as 200
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:29:43 GMT-3